Fundamentals of Industrial Hygiene 6th Edition Chapter 4: The Ears Compiled by Allen Sullivan, Assistant Professor, Safety and Health Management Central Washington University
Ear Anatomy External Ear auricle (pinna) external auditory canal vibrissae cerumen
Ear Anatomy (cont.) Middle Ear tympanic membrane ossicular chain malleus (hammer) incus (anvil) stapes (stirrup) eustachian tube oval window
Ear Anatomy (cont.) Inner Ear cochlea vestibular system
Pathology of the External Ear Auricle (pinna) trauma frostbite dermatitis and infection Auditory Canal foreign objects live insects wax impaction narrowing of ear canal
Pathology of Middle Ear Eustachian Tube plugged v. open Eardrum infections perforations/rupture Ossicular Chain fixation interruption
Pathology of Inner Ear Cochlea Vestibular System Eighth Cranial Nerve congenital/developmental defects systemic diseases (MS, diabetes) infection (mumps) exposure to noise exposure to toxins (medications, solvents) circulatory problems (stroke) trauma (concussion, skull fracture) Vestibular System Eighth Cranial Nerve presbycusis tinnitus
Hearing Measurement Air Conduction Testing Bone Conduction Testing audiogram
Effects of Noise Exposure Noise-Induced Hearing Loss factors sound level frequency distribution duration temporal distribution type of sound energy individual differences concurrent exposure to ototoxins
Non-Auditory Effects of Noise Communication loudness and clarity Speech Sounds vowels and consonants Physiological Response blood pressure sleep disturbance pregnancy Background Noise Quality of Life